Essentially all of today's electronic systems require some form of power conversion, be it changing alternating current voltage levels, converting alternating current to direct current, changing direct current voltage levels, or combinations thereof. In situations where changing voltage levels of direct current are needed, a switching voltage regulator is a preferred solution. A switching voltage regulator can be used to step-up voltage levels (boost) or step-down voltage levels (buck) or a combination of both.
A switching voltage regulator makes use of an inductor, a transformer, or a capacitor as an energy-storage element to transfer energy from an input to an output in discreet packets. Feedback circuitry can be used to regulate the energy transfer to maintain a constant voltage level within the load limits of the circuit. A burst-mode switching voltage regulator is popular for its fast transient response since there is no requirement for an error amplifier or a compensator in the feedback path. Typically, a burst-mode switching voltage regulator will have a low equivalent series resistance (ESR) capacitor at its output to help reduce output ripples.
One disadvantage of the prior art is that if the ESR capacitor has too small of a resistance, then the burst-mode switching voltage regulator may not be stable.
A second disadvantage of the prior art is that if the ESR capacitor has too large of a resistance, then the burst-mode switching voltage regulator may have significant ripples in its output.